This invention relates to a vibration-transmitting tablet and manufacturing method of the tablet and coordinate-input apparatus. More particularly, the present invention relates to a coordinate-input apparatus which detects elastic-wave vibration, inputted from a vibration source and propagated on a vibration-transmitting tablet as a coordinate input surface, and obtains the position (coordinate) of vibration source based on transmitting time of the elastic-wave vibration on the vibration-transmitting tablet, and vibration-transmitting tablet used in the coordinate-input apparatus and manufacturing method of the vibration-transmitting tablet.
Conventionally, a method for calculating the distance between two points by utilizing an ultrasonic wave is known. Such a method is applied to a coordinate input apparatus disclosed in Japanese Patent Publication No. 5-60615, for example. The apparatus generates vibration by inputting vibration, from a coordinate-input pen as a coordinate-input designation tool, onto a vibration-transmitting tablet as a coordinate input surface. The vibration is detected by a plurality of sensors attached to the vibration-transmitting tablet. The coordinate position where the vibration has been input is calculated by measuring respective time periods from the point where the vibration has been inputted to points where the vibration reaches the sensors (see FIG. 9).
In this apparatus, a coordinate position designated by the coordinate-input pen can be outputted to an information processing apparatus such as a personal computer, thus characters and figures can be easily inputted into the information processing apparatus.
However, the above conventional art has the following problems.
In the conventional coordinate-input apparatus, the vibration from the coordinate input pen, that generates vibration as the coordinate-input designation tool, is detected, via the tablet by a plurality of sensors (vibration detecting devices) attached to the vibration-transmitting tablet. This thickens the apparatus by the thickness of the sensors, and in a case where the apparatus is constructed into a portable type apparatus, for example, a problem occurs in portability of the apparatus.
Further, this coordinate-input apparatus has its operational principle to respectively obtain the distances between the coordinate-input point and the respective sensors, and output the position of the input pen based on the obtained distance information. To calculate the coordinate position with high precision, the absolute positions of the sensors must be precisely positioned and the sensors must be fixed at the absolute positions. Accordingly, in manufacturing the apparatus, the positions of sensors must be strictly managed. In case of mass production, productivity is lowered due to this management of the sensor positions, which results in manufacturing of the apparatus with high costs.